Hair curler with plastic integral ring

ABSTRACT

A hair-curler having an open cylindrical cavity at one end and having an outer plastic casing formed around an inner metal heataccumulating body. The open cavity allows the curler to be mounted onto a pin-formed heating element. The outer plastic casing is bent inwardly over and firmly grasping the end edge of the heat-accumulating body in order to effect a tight bond between the two surfaces and in order to insulate the metal surface of the inner heat-accumulating body. Apparatus for forming the outer casing over the inner heat-accumulating body.

United States Patent 1 Johansen [451 Nov. 20, 1973 HAIR CURLER WITHPLASTIC INTEGRAL RING [75] Inventor: Bent Georg Johansen, Kalundborg,

Denmark [73] Assignee: Bristol-Myers Company, New York,

22 Filed: Oct. 12,1971

21 Appl.No.: 188,372

[30] Foreign Application Priority Data Oct. 16, 1970 Denmark 5281/70[52] US. Cl 132/33 R [51] Int. Cl A4511 2/12 [58] Field of Search,132/33 R, 39, 40;

[56] References Cited UNITED STATES PATENTS Pedersen 2,579,466 12/1951Birkland 220/67 X 3,533,418 10/1970 DeMestral 132/40 3,161,202 12/1964Mecca 132/40 1,568,790 1/1926 Wright 229/5.6 3,428,238 2/1969 Shelby eta1. 220/67 X Primary Examiner-Louis G. Mancene Assistant ExaminerJ. N.Eskovitz Att0rneyWilliam F. Moss, III et a1.

1 Claim, 8 Drawing Figures E I I I I I I I I HAIR CURLER WITH PLASTICINTEGRAL RING This invention is concerned with an improved hair curlerbeing adapted for mounting onto a pin-formed heater element. The curleris comprised of an outer plastic casing and an inner metalheat-accumulating body. At one end of the curler is an open cylindricalcavity for receiving a pin-formed heating element. The invention isfurther concerned with the method of attaching the outer casing to theinner heat-accumulating body and to the apparatus used in such method.

In the past, hair curlers adapted for heating from the inside of thecurler via a pin-formed heating element have been so constructed as toexpose a portion of the metal inner heat-accumulating body so that thedanger of touching and possible burning of ones fingers is present.Moreover, such curlers on occasion, particularly after a period of usehave exhibited separation between the inner and outer casings.

It is accordingly an object of the present invention to provide animproved curler which substantially eliminates these objectionablefeatures and at the same time, affords a simple and economical methodfor making such curlers.

In accordance with the invention an essential feature of the curler isthat the end section of the plastic outer casing at the open end of thecavity is bent inwardly over and firmly grasping the end edge of theinner heat accumulating body. When this is accomplished the end sectionis formed along the inner wall of the cavity to cover the previouslyexposed metal surface and acts as a heat insulatingring. Thus, theplastic casing of the curler is attached to the heat-accumulating bodywithout the risk of the casing working loose from the inner body and aconvenient and effective heat-insulating ring is formed along the innerwall of the cavity.

Since deformed plastic materials have a certain demonstratable memory,in accordance with the invention, the bent edge section is provided withring-formed or rib-formed embossments which are form-stabilized. Suchembossment tends to counter the tendency of the plastic material toassume its original shape.

The invention will be more clearly understood by reference to thedrawings in which:

FIG. 1 is a side elevational view showing a die or male forming memberof the apparatus used in the method for making curlers in accordancewith the invention;

FIG. 2 is a side elevational view showing the outer plastic casingcontaining the inner heat-accumulating body, ready for attachment bymeans of the forming member shown in FIG. 1;

FIG. 3 is a side elevational view showing the curler and die after theend edge of the plastic casing is bent;

FIG. 4 is a side elevational view showing a die for makingform-stabilizing embossments on the bent end edge of the plastic casing;

FIG. 5 is a side elevational view showing the outer plastic casingcontaining the inner heat-accumulating body, ready for treatment bymeans of the die shown in FIG. 4;

FIG. 6 is a side elevational view showing the die of FIG. 4 engaging thehair curler shown in FIG. 5 to produce embossments;

FIG. '7 is a plan view showing the completed hair curler viewed from itsopen end; and

FIG. 8 is a cross-sectional view of another embodiment showing thetwo-stage die.

According to the invention, the apparatus for attaching the outerplastic casing to the inner heataccumulating body of the hair curlerincludes a press tool with a die having a circular bead-producing groovein its bottom. The heat-accumulating body having an outer plastic casingmounted thereon is placed beneath the die with its open end facingupward. As the die moves downward the end edge section of the outerplastic casing engages the die so that by a rolling and bending movementin the bead-producing groove, which is of circular arc cross-section, itis caused to lay along the inner side of the axially extending end edgeof the inner body.

The apparatus may have a die which is provided near its bottom withring-formed or rib-formed projections or grooves adapted for producingplastic-stabilizing embossments in the bent edge section of the plasticcasing. By using this type of die the plastic is treated so that itstendency to assume its original form is eliminated.

The presentinvention contemplates using each of the above discussed diessequentially or providing for one die to be telescoped by conventionalmeans within the other.

In order to prevent any compression of the plastic casing in the axialdirection during the press or forming operation, the apparatus may beprovided with a clamping tool for use on the outside of the curler. Theinner wall of the clamping tool is provided with depressions which areadapted for receiving pin-formed or web-formed projections located onthe outer surface of the curler, depending on the particular design ofthe outer surface of the curler.

The plastic casing will usually be manufactured separately and pulledonto the heat-accumulating body directly before the parts are united atthe end edge. However, it is possible to mold the plastic casing on theheat-accumulating body. According to the preferred embodiment of theinvention, the plastic casing used is of such length that in its mountedposition it extends beyond the open end of the curler, and by the colddeformation the projecting extension is rolled over the end edge of theheat-accumulating body.

Referring now to the drawings, the hair curler consists of an outerplastic casing I mounted on the outer side of a heat-accumulating body 2comprised of a double-walled cylindrical container. Between thecontainer walls is a heat-accumulating material such as, for example,erythrite designated in FIG. 2 as 2a. The inside walls of the containerdefine an inner cavity 2b for receiving a pin-formed heating element(not shown). At its open end the heat-accumulating body 2 has an uprightaxial end edge 3 at the joint between the outer and inner containerwalls. As shown in FIG. 2 the plastic outer casing 1 extends above theinner body with an end edge section 4 which is bent inwardly by rollingand caused to rest around the end edge 3 when die 5, shown in FIG. 1, ismoved downwardly over the end edge section 4. Die 5 is provided in itsbottom with a circular bead-producing groove 6 having a circular arccross-section located so that during the downward movement of the die,groove 6 guides the end edge section 4 to assume the form as shown inFIG. 3, where die 5 is in the down stroke or bottom position. At thecompletion of the down stroke of the die the end edge section 4 extendsannularly along the inner wall of the heat-accumulating body to act as aheatinsulating protective integral ring. The bent end edge section 4 notonly serves to protect the user against inadvertent contact with themetal inner wall surface of the heataccumulating body, but it alsoserves to retain the plastic casing 1 to the heat-accumulating body 2and prevents the casing from separating.

In FIG. 4, die 7 is shown having a bottom shoulder 8 and a plurality ofrib-like projections 9.

FIG. 5 shows the outer plastic casing 2 after die 5 has engaged and bentthe end edge section 4. FIG. 6 shows die 7 in the down position,shoulder 8 engaging end edge section 4 to produce an annular deformationor embossment 11 shown in FIG. 7. By using die 7 both rib-formeddeformations 9a and groove-formed deformations l 1 may be produced bycontact of projections 9 and shoulder 8 with end edge section 4.

The hair curlers of the present invention are provided with flangedsections 10 at each end which facilitate easy and safe handling andreduce the tendency of the wound hair to slide ofi the curler at theends. During the pressing operation with dies 5 and 7, flange 10 issupported by means of a simple clamping tool positioned along the outersurface of 10. However, improved clamping and support is obtained whenthe clamping tool has an inner wall with depressions 13 for receivingprojections 12 located on the outer surface of the curler.

The press tool may be so designed that the heataccumulating body 2 withthe plastic casing I mounted thereon is at first brought into positionbeneath the die 5 and brought into position beneath the die 7 in thesubsequent operation as indicated in the drawings.

However, the die 7 may also be designed as to be axially displaceable inthe die 5 and be brought to operate as soon as the die 5 has been passedinto the position indicated in FIG. 8.

What is claimed is:

1. A hair curler adapted for convenient and safe handling and for moreefficient retention of wound hair on the outer surface of the curlercomprising a substantially tubular outer casing having side walls, aclosed end and an opposite open end, and an inner heataccumulatingcontainer disposed within said outer casing and having an axis extendingparallel to the longitudinal axis of said tubular casing, said innercontainer comprising an inner wall and an outer wall forming a hollowcylindrical heat conductive sleeve having a central cavity adapted topermit the insertion of a heating element in heat conductive contact,said outer wall having a terminal portion bent over said inner wall toform end edge sections, said sleeve containing a heatabsorbing material,said outer casing side walls having end edge sections bent inwardly overthe end edge sections of the inner container to form an integral annularring along the inner wall of the heat-accumulating body thereby joiningthe outer casing to the inner container, wherein said bent end sectionsare comprised of formstabilizing embossments said curler furthercomprising opposite radial end flanges and disposed between said endflanges a central section having projections on its outer surface, saidend flanges having a diameter greater than the diameter within saidcentral section.

1. A hair curler adapted for convenient and safe handling and for moreefficient retention of wound hair on the outer surface of the curlercomprising a substantially tubular outer casing having side walls, aclosed end and an opposite open end, and an inner heat-accumulatingcontainer disposed within said outer casing and having an axis extendingparallel to the longitudinal axis of said tubular casing, said innercontainer comprising an inner wall and an outer wall forming a hollowcylindrical heat conductive sleeve having a central cavity adapted topermit the insertion of a heating element in heat conductive contact,said outer wall having a terminal portion bent over said inner wall toform end edge sections, said sleeve containing a heat-absorbingmaterial, said outer casing side walls having end edge sections bentinwardly over the end edge sections of the inner container to form anintegral annular ring along the inner wall of the heat-accumulating bodythereby joining the outer casing to the inner container, wherein saidbent end sections are comprised of form-stabilizing embossments saidcurler further comprising opposite radial end flanges and disposedbetween said end flanges a central section having projections on itsouter surface, said end flanges having a diameter greater than thediameter within said central section.